It is known that an addition polymer of a cycloolefin such as norbornene or tetracyclododecene, and an addition copolymer of a cycloolefin such as norbornene or tetracyclododecene with an α-olefin such as ethylene or propylene have high heat resistance, high transparency, low water absorbance, low refractive index and good electrical properties, and therefore, the addition polymers and copolymers are suitable for optical parts such as optical lens, optical memory disc, optical fiber and optical film, and electronic and electrical parts such as electrically insulating part.
In recent years, many proposals have been made with regard to a catalyst used for the production of the addition polymers and copolymers, and a process for producing the addition polymers and copolymers. For example, nickel catalysts and palladium catalysts have been proposed as a catalyst for addition polymerization of a cycloolefin in Japanese Patent Publication (hereinafter referred to as “JP-A”) No. H09-508649 and International Publication No. WO00/20472. Metallocene catalysts and post-metallocene catalysts have been proposed as a catalyst for addition copolymerization of a cycloolefin with an α-olefin in JP-A H03-45612 and JP-A 2004-331966.
However, the nickel catalysts and palladium catalysts proposed in JP-A H09-508649 and WO00/20472 exhibit a high activity for the addition polymerization of a cycloolefin, but, they do not exhibit at all an activity for the addition copolymerization of a cycloolefin with an α-olefin. The metallocene catalysts and post-metallocene catalysts, proposed in JP-A H03-45612 and JP-A 2004-331966, exhibit a high activity for the addition copolymerization of a cycloolefin with an α-olefin, but, they exhibit a poor activity for the addition polymerization of a cycloolefin. Therefore, a catalyst capable of exhibiting a high activity for both of the addition polymerization of a cycloolefin and the addition copolymerization of a cycloolefin with an α-olefin has been desired.
In view of the foregoing, a CGC type metallocene catalyst having a fluorenyl group has been proposed as a catalyst capable of exhibiting an activity for both of the addition polymerization of norbornene and the addition copolymerization of norbornene with ethylene in JP-A 2004-107442. The catalytic activity is described as relatively high in this patent publication, but, the catalytic activity is not to a sufficient extent from an industrial viewpoint.
It is described in Journal of the American Chemical Society, vol. 126, pp 16716-16717, 2004, that, in a CGC type metallocene complex having a substituted fluorenyl group, a transition metal is bonded to the substituted fluorenyl group in an η1 mode; and further that a catalyst comprised of this CGC type metallocene complex exhibits a high activity especially for polymerization of a long-chain α-olefin. However, the catalytic activity of this CGC type metallocene complex catalyst for a cycloolefin is not known.
A complex comprising a group 4 transition metal atom having coordinated thereto a neutral Lewis base is described in claim 1 of JP-A H05-507756. However, any specific example of this complex is not mentioned in this patent publication. In this patent publication, only a compound having a substituted cyclopentadienyl group bonded to a group 4 transition metal compound in an η5 mode is specifically described as a group 4 transition metal compound constituting the above-mentioned complex.